secure data erasing

[David Wolfskill]

On Wed, Dec 07, 2005 at 09:09:56PM -0800, Alison at wsrcc.com wrote:
> 
> alvin at Mail.Linux-Consulting.com (Alvin Oga) writes:
> > ....

> > the itty-bitty section ofthe disk under the head at the time of the
> > hammer might get destroyed, but the rest of data on the platter is
> > still intact
> 
> As suggested above, destroying the heads (perhaps with tweezers) is a
> lot easier than denting the platters with hammers.  Damaged heads
> won't prevent someone from putting the platters in another system and
> reading them, but then we're talking about a fairly motivated and
> sophisticated snoop.
>...

For at least some consumer-grade drives, applying force (at room
temperature & pressure) is very unlikely to "dent" a platter.

I disassembled a drive that was to be thrown away.  (I believe it was an
IBM drive that was retired after it reported read errors.)

I thought it would be amusing to deform one of the platters to a
hyperbolic paraboloid (a "saddle curve"); I proceeded to do that (by
hand).

The platter resisted deformation; I pressed harder.

It shattered.

I was surprised -- and I am thankful that no shards struck my eyes.

I am reasonably confident that reconstructing any data that may have
resided on that drive would not be worth the effort -- if, indeed, it
might be possible.  (We were picking shards out of the carpet of that
office for months....)

Peace,
david
-- 
David H. Wolfskill				david at catwhisker.org
It is courteous to reduce quoted text to just that needed to establish context.

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